Over one quarter of Earth's population does not have adequate access to freshwater. Inadequate access to freshwater is detrimental, as it can lead to disease and malnutrition, limit agricultural development, and inhibit economic growth.
In contrast to freshwater, saltwater is readily available. Saltwater in the form of seawater constitutes about 97% of the water on Earth. Unless seawater is sufficiently desalinated, though, it is not only undrinkable but unsuitable for agriculture. “Desalination” refers to the process of removing anions and cations from saltwater. Seawater typically has a salt concentration of about 3.5% salt by mass; that is, about 35 grams of dissolved salt per liter of water. Another source of saltwater is salty, underground aquifer water, also known as “brackish water”. The salt concentration of brackish water typically ranges from less than 1% to more than 18% salt by mass. In contrast, drinkable water typically has a salt concentration of, at most, about 0.04%. Desalination also has industrial applications; for example, waste saltwater can be desalinated for re-use and to produce a low volume, concentrated brine for disposal.
Given the need for freshwater, and given the abundance of saltwater, including saltwater that is industrial waste, there exists a continued need for methods and systems for producing freshwater by desalinating saltwater.